I would also like a pet fee option, and for that fee to increment with the number of pets, i.e. $20/night for one dog, $30/night for two dogs.
I would also like to see Airbnb allow hosts to enable certain types of pets. Our property is dog-friendly, but we're not able to take cats because of our family's own allergies.
We often have guests book for a dog and a cat, and we have to cancel their reservation and explain that we meant "dogs only" (which is very clearly stated in the listing, but who reads anymore? lol) Airbnb's search filter is on "Pets allowed" when it could be improved to allow more granular search (i.e. cats, dogs, ferrets, rocks, etc.)